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# cancelRequest(withError:)

Tells the host app to cancel the app extension request, with a supplied error.

```
func cancelRequest(withError error: any Error)
```

## Parameters

`error`

The error object to return. It must be non-`nil`.

## Discussion

On return, the `userInfo` dictionary of the [`NSError`](/documentation/Foundation/NSError) object contains a key named [`NSExtensionItemsAndErrorsKey`](/documentation/Foundation/NSExtensionItemsAndErrorsKey) which has as its value a dictionary of [`NSExtensionItem`](/documentation/Foundation/NSExtensionItem) objects and associated [`NSError`](/documentation/Foundation/NSError) instances.

## See Also

  [App Extension Programming Guide](https://developer.apple.com/library/archive/documentation/General/Conceptual/ExtensibilityPG/index.html#//apple_ref/doc/uid/TP40014214)


---

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